You are the air that I breathe
Is air oxygen or what?
Is air gas? The answer is more complex than this. What we call air is a mixture of many gases and tiny dust particles. All living things live and breathe in this clear gas. The two main gases in gases in air are nitrogen and oxygen. The air oxygen concentration is around 21% of the total, nitrogen accounts to 78% and the remaining 1% is a mixture of other gases such as carbon dioxide, neon and hydrogen. This air mixture hasn’t always been so: in some periods the oxygen levels soared to a whopping 35% whereas at the end of the Permian a concentration of carbon dioxide drove many species to mass extinction. The specific balance of air contents at the moment makes life possible on Earth.
What about the tiny particles?
Air is mostly gases but it holds tiny particles – such as dust or pollen – called aerosols. Some aerosols are polluting like smoke, or pollutants caused by power plants or cars. Because air carries them around there can be a concentration of them so high that it makes it difficult for plants and animals to breathe. Another thing that air holds is water: in fact what we call humidity is the amount of water air can carry before it rains.